In recent years, flat panel displays have been utilized in various products and fields, and there is demand for flat panel displays having larger sizes, higher picture quality, and lower power consumption.
In view of such circumstances, organic electroluminescent (EL) display devices provided with organic EL elements utilizing the electroluminescence of organic materials are attracting much attention as flat panel displays due to their excellent qualities, such as low voltage driving, high responsiveness, and self-luminosity, while being in a completely solid state.
For example, in an active matrix organic EL display device, a thin film organic EL element is provided on a substrate on which a thin film transistors (TFT) is provided. In an organic EL element, an organic EL layer including a light-emitting layer is layered between a pair of electrodes. One of the pair of electrodes is connected to the TFT. An image display is performed by applying a voltage between the pair of electrodes and causing the light-emitting layer to emit light.
In organic EL display devices as described above, RGB sub pixels that emit red (R), green (G), and blue (B) light are provided to display color images.
Furthermore, in organic EL display devices as described above, the color reproducibility of red, green, and blue light is unproved by providing a color filter layer on a counter substrate opposing the substrate, for example.
In conventional organic EL display devices described above, a configuration has been proposed in which a sealing film having an organic layer and an inorganic layer layered in an alternating manner is provided on an organic EL element, as disclosed in the following PTL 1, for example. According to this conventional organic EL display device, the sealing film makes it possible to prevent the organic EL element from degrading due to moisture or oxygen and improve the reliability of the device.